The Canada native, 33, has kept quiet about her musician boyfriend, but the couple have stepped out on occasion for red carpet events, reported Us magazine.
Pare has also showed off her own musical talents since moving from Montreal to LA a decade ago.
Pare joined the 'Mad Men' cast as a secretary at Sterling Cooper Draper Pryce in 2010, and became a central character after the shocking season four finale when Don weds Megan nearly out of the blue.